G-rotor pump

ABSTRACT

In a G-rotor pump for the conveyance of fuel in a motor vehicle, pockets are arranged in an external rotor. Dirt particles in the fuel can collect in the pockets. A wear of regions of the external rotor and of the internal rotor which roll on one another is consequently kept particularly low.

CLAIM FOR PRIORITY

[0001] This application claims priority to International Application No. 10221784.6, which was filed in the German language on Jun. 4, 2002, which is hereby incorporated by reference.

TECHNICAL FIELD OF THE INVENTION

[0002] The invention relates to a G-rotor pump which is used as a fuel pump in a motor vehicle, and in particular, having an external rotor and an internal rotor moveable relative to the external rotor, in which pump a conveying space is delimited between the external rotor and the internal rotor.

BACKGROUND OF THE INVENTION

[0003] G-rotor pumps are often also designated as geared pumps or eccentric pumps, and are known from practice. In the conventional G-rotor pump, the external rotor has an internal toothing and the internal rotor has an external toothing corresponding to the internal toothing. The external toothing has one tooth less than the internal toothing, with the result that the conveying space is formed. When the internal rotor or the external rotor is driven, the external toothing of the internal rotor rolls over the internal toothing of the external rotor. When the G-rotor pump is used as a fuel pump, there is often the problem that dirt particles infiltrate between the rotors and lead to their abrasion and consequently to a reduced service life of the G-rotor pump. The G-rotor pump is therefore usually preceded by a particularly close-mesh filter. Since dirt particles may quickly clog the filter, however, this design leads to a highly cost-intensive maintenance of the G-rotor pump.

[0004] One disadvantage of the known G-rotor pump is that it is highly sensitive to dirt particles located in the flow.

SUMMARY OF THE INVENTION

[0005] In the invention, pockets are arranged in the external rotor and/or the internal rotor.

[0006] According to one embodiment of the invention, the dirt particles can collect in the pockets and are consequently kept away from rotor tooth flanks rolling on one another. The dirt particles are subsequently flushed out of the pockets or the pockets are permanently filled with the dirt particles. The pockets in this case require at least a size corresponding to the quantity of dirt particles located in the flow. As a result, the G-rotor pump according to the invention has a particularly long service life, even when the liquid to be conveyed is heavily contaminated. The G-rotor pump therefore requires no particularly close-mesh filter. The G-rotor pump according to the invention is consequently particularly suitable for use as a fuel pump.

[0007] According to another embodiment of the invention, the dirt particles accumulate, as a result of the flow, in the pockets and can remain there if the pockets are designed as depressions arranged in tooth bottoms of the internal rotor.

[0008] According to another embodiment of the invention, the dirt particles can be conveyed out of the pockets in a simple way by the centrifugal forces if the pockets are designed as depressions arranged in the tooth bottoms of the internal rotor.

[0009] The G-rotor pump according one embodiment of the invention has a high capacity for the uptake of dirt particles when the pockets are arranged in all the tooth bottoms of the external rotor or tooth bottoms of the internal rotor.

[0010] According to still another embodiment of the invention, a wear of the edges of the internal rotor and of the external rotor can be kept particularly low when the pockets extend over the entire height of the external rotor and/or the internal rotor.

[0011] According to yet another embodiment of the invention, the pockets can be manufactured in a particularly simple way when they have a groove-shaped design. The bottom of the pockets could have an acute-angled or angular design. According to another embodiment of the invention, a contribution to simplifying the collection of dirt and the discharge of dirt particles is made when the pockets have a radius in their bottom region. In this case, likewise, the notch effect of the pockets is kept particularly low.

[0012] A contribution to further lengthening the service life of the G-rotor pump according to the invention is made when the external rotor and/or the internal rotor are/is manufactured from metal.

[0013] A contribution to reducing the manufacturing costs of the G-rotor pump according to one embodiment of the invention is made when the external rotor and/or the internal rotor are/is manufactured from plastic.

[0014] In still another embodiment, as a result of the arrangement of the pockets, the bottom and the cover can be manufactured from plastic and/or sintered metal.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 shows a longitudinal section through a fuel feed unit with a G-rotor pump according to the invention.

[0016]FIG. 2 shows an enlarged, sectional illustration through the G-rotor pump from FIG. 1 along the line II-II.

[0017]FIG. 3 shows a sectional illustration through another embodiment of the G-rotor pump.

DETAILED DESCRIPTION OF THE INVENTION

[0018]FIG. 1 shows a fuel feed unit 1 with a housing 3 receiving an electric motor 4 and the G-rotor pump 2. The G-rotor pump 2 has a bottom 5 and a cover 7 held at an intended distance from the bottom 5 via a spacer 6. The spacer 6 and the cover 7 are manufactured in one piece here. Between the cover 7 and the bottom 5 is arranged an internal rotor 9 fastened on a shaft 8 of the electric motor 4. The shaft 8 has, for the rotationally fixed drive of the internal rotor 9, a flattening 10 and a step 11. As a result, the internal rotor 9 can be connected to the shaft 8 in the depicted position. The internal rotor 9 has an external toothing 12, illustrated in FIG. 2, which engages into an internal toothing 13 of an external rotor 14.

[0019] The cover 7 has an inlet 15 and the bottom 5 an outlet 16 of the G-rotor pump 2. Fuel is thereby taken in via the cover 7 and flows through the G-rotor pump 2 axially. The housing 3 of the fuel feed unit 1 has a connection piece 17 for connecting a line, not illustrated. For clarity, the flows marked by arrows in the drawing.

[0020]FIG. 2 shows an enlarged, sectional illustration through the G-rotor pump 2 from FIG. 1 along the line II-II. To simplify the drawing, the housing 3 and the spacer 6 of the G-rotor pump 2 are not illustrated. The external toothing 12 of the internal rotor 9 has one tooth less than the internal toothing 13 of the external rotor 14. This results in a conveying space 18, through which the feed liquid is conveyed from the inlet 15, illustrated in FIG. 1, to the outlet 16. Moreover, In FIG. 2, directions of rotation of the internal rotor 9 and of the external rotor 14 are marked by arrows. In tooth bottoms of the internal toothing 13 of the external rotor 14 are arranged pockets 19 which extend over the entire height of the external rotor 14. Dirt particles located in the feed liquid accumulate in these pockets 19. This prevents the dirt particles from rubbing against one another on the flanks of the internal toothing 13 and of the external toothing 12.

[0021]FIG. 3 shows a sectional illustration through another embodiment of the G-rotor pump 2 which, like that from FIG. 2, has an internal rotor 20 with an external toothing 21 and an external rotor 22 with an internal toothing 23. This embodiment differs from that from FIG. 2 in that pockets 24 for the uptake of dirt particles are arranged in the tooth bottoms of the external toothing 21 of the internal rotor 20. By contrast, tooth bottoms of the internal toothing 23 of the external rotor 22 are made smooth. By virtue of this design, when liquid is being conveyed, dirt particles are taken up in the pockets 24 of the internal rotor 20 and are thrown out again by means of centrifugal forces. 

What is claimed is:
 1. A G-rotor pump used as a fuel pump in a motor vehicle, comprising: an external rotor; and an internal rotor moveable relative the external rotor, in which pump a conveying space is delimited between the external rotor and the internal rotor, wherein pockets are arranged in at least one of the external rotor and the internal rotor.
 2. The G-rotor pump as claimed in claim 1, wherein the pockets are designed as depressions arranged in tooth bottoms of the external rotor.
 3. The G-rotor pump as claimed in claim 1, wherein the pockets are designed as depressions arranged in tooth bottoms of the internal rotor.
 4. The G-rotor pump as claimed in claim 1, wherein the pockets are arranged in the tooth bottoms of the external rotor or tooth bottoms of the internal rotor.
 5. The G-rotor pump as claimed in claim 1, wherein the pockets extend over an entire height of the external rotor and/or of the internal rotor.
 6. The G-rotor pump as claimed in claim 1, wherein the pockets have a groove-shaped design.
 7. The G-rotor pump as claimed in claim 1, wherein the pockets have a radius in a bottom region.
 8. The G-rotor pump as claimed in claim 1, wherein at least one of the external rotor and the internal rotor are manufactured from metal.
 9. The G-rotor pump as claimed in claim 1, wherein at least one of the external rotor and the internal rotor are manufactured from plastic.
 10. The G-rotor pump as claimed in claim 1, wherein a bottom plate and a cover of the G-rotor are manufactured from plastic and/or sintered metal. 